计算对象数组中的特定键值 [英] Count particular key value from array of object

问题描述

我有以下JSON数组，我想创建对象表单状态键计数

I have following JSON array I want to create object form status key count

[
  {
    "id": "65:0",    
    "status": "ORANGE"
  },
  {
    "id": "65:0",
    "status": "GREEN"
  },
  {
    "id": "65:0",
    "status": "ORANGE"
  },
  {
    "id": "65:0",
    "status": "YELLOW"
  },
  {
    "id": "65:0",
    "status": "RED"
  },
  {
    "id": "65:0",
    "status": "GREEN"
  },
  {
    "id": "65:0",
    "status": "GREEN"
  },
   {
    "id": "65:0",
    "status": "ORANGE"
  },
  {
    "id": "65:0",
    "status": "YELLOW"
  },
  {
    "id": "65:0",
    "status": "GREEN"
  }
] 

要计算状态键值并创建以下对象

Want to count status key value and create the following Object

{
 'ORANGE' : 3,
 'GREEN' : 4,
 'YELLOW' : 2,
 'RED' : 1,
}

推荐答案

使用

var data = [{
  "id": "65:0",
  "status": "ORANGE"
}, {
  "id": "65:0",
  "status": "GREEN"
}, {
  "id": "65:0",
  "status": "ORANGE"
}, {
  "id": "65:0",
  "status": "YELLOW"
}, {
  "id": "65:0",
  "status": "RED"
}, {
  "id": "65:0",
  "status": "GREEN"
}, {
  "id": "65:0",
  "status": "GREEN"
}, {
  "id": "65:0",
  "status": "ORANGE"
}, {
  "id": "65:0",
  "status": "YELLOW"
}, {
  "id": "65:0",
  "status": "GREEN"
}];

var res = data.reduce(function(obj, v) {
  obj[v.status] = (obj[v.status] || 0) + 1;
  return obj;
}, {})

console.log(res);

尽管您可以使用 <具有相同代码的c2> 方法.

Although you can use Array#forEach method with the same code.

var res = {};
data.forEach(function(v) {
  res[v.status] = (res[v.status] || 0) + 1;
})

var data = [{
  "id": "65:0",
  "status": "ORANGE"
}, {
  "id": "65:0",
  "status": "GREEN"
}, {
  "id": "65:0",
  "status": "ORANGE"
}, {
  "id": "65:0",
  "status": "YELLOW"
}, {
  "id": "65:0",
  "status": "RED"
}, {
  "id": "65:0",
  "status": "GREEN"
}, {
  "id": "65:0",
  "status": "GREEN"
}, {
  "id": "65:0",
  "status": "ORANGE"
}, {
  "id": "65:0",
  "status": "YELLOW"
}, {
  "id": "65:0",
  "status": "GREEN"
}];

var res = {};
data.forEach(function(v) {
  res[v.status] = (res[v.status] || 0) + 1;
})

console.log(res);

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